Interlocking system for railroads



March 3, 1931;

SN. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed Nov.

Patented Mar. 3, 1931 UNIT rails as r SEDGWICK N. WIGHT, ornoonns'rEnnnW YOBK, ASSIGNOR To GENERAL RAILWAY "r 'oF I e SIGNALCOMPANY, OF ROCHESTER, NEW YORK 'IN'TERLOGKING sYsrEi/rros RAILROADS 7'Application filed November 8, 1929. Serial No. 405,625.

This invention relates to interlocking systems' and more particularly tothe provision. of meansfor controlling ail-interlocking plant located ata great distance from thedispatchers oflioe economically and over aco1npara tively few line wires; p

When two railroad tracks cross each other at the same grade 1t 1snecessary to provide interlocking means to prevent a collision be 1,2tween two trains at such crossing. In. a'c-' cordance with the usualpractice-there are not only provided signals of the stop-a-nd-stay typeat the approach to such a crossing, but derails are also provided, andthese derails are in their active derailing position normally and areonly cleared when the derails of the conflicting route are in theiractive position. lnaccordance with the present invention it is proposedto operatethe derails and signals of one of the conflicting tracks overseparate circuits, and to indicate over these same-circults when thederails are operated, when a train passes over such derails and whichor" the signals 1s 1n a proceed POSltlOIl;

Other objects, purposes and characteristic features of the invention arein part apparent from the accompanying drawings and will in part bepointed out in the description hereinaiter.

a? In describing the invention in detail reference will be made to theaccompanying drawings, in which the portion in the dotted rectangle atthe left indicates the apparatus located in the interlocking tower andthe re maining portion indicates the apparatus at the distant railroadcrossing.

. Referring to the drawings there have been shown an east and westtrack' EW having rails 1, and a north and south track NS hav- 49 ingrails 2, of two conflicting railway systems.

The present invention has been shownapplied to the east andwest system,which has associated therewith an east bound derail DRE and west boundderail DRW. These derails are each operated by a switchmachine mechanismof the usual construction, which has been conventionally illustrated.Train travel is directed'over the derail DRE through the medium of thestop-and-stay signal and [I train travel is directed over the west b Hcordance with traffic conditions.

derail DRW by the stop-and-stay signalSW,

home relays EH and WH beingprovided forcontrolling these signals,respectively, ac-

The track section between the signals SE and SIV is in sulated from theremaining track by insulating joints 3, and is provided with the usualtrack circuit includinga track relay. T and a track battery 4- Thederails DRE and DRW' are controlled through the medium of a controlrelay 2Z, whereas the signals SE and SW are controlled in accordancewith 'trafiic conditions by the control relay 1Z, the operated conditionof the track relay T also entering into the control of the signals SEand SW, whereas the operation of the derails DRE and DR? is dependentupon the relay 2Z and the condition of train travel as determined by anapproach locking arrangement such as shown 7 1n my prior applicatiomSer.No.120,4:23, filed purpose of which will be described herein indicateoccupancy of the track'circuit at the a distant interlocking plant, andthe indicating lamp I indicating operation of the derails DRE and DRW.There are also pro vided in the interlocking tower IT relays IR, 23, andIX, the purpose of which will bepointed out in the operation ofthesystem hereinafter. Having now pointed. out the various elements ofthe system, it 'is deemed expedient to take up the operation thereof toobserve their coaction. A

079emtz'0nsr Let us assume that the inter.

locking operator has been informed by suitable means, not shown, thatthere is an east bound train approaching on the track EW, and thathewishes to clear-the signal SE to allow such train to pass over therailroad crossing. In. order to do this he will'first be required tooperate the two derails DRE and DRW to their abnormal ineffectiveposition. This will be done by moving the lever L to the right therebyclosing the following circuit for the relay 2Z: beginning at thepositive terminal of the battery 10, wires 11 and 12, lever L wires 13and l l, winding of the relay 2R, line wire 15, front contact 16 of therelay 20S, wire 17, Winding of the relay 2Z, wires 18 and 19, contact 20of the signal SS, wire 21, signal blade contact 22 of the signal SN,wires 23 and 24, common return wire C, Wires 25 and 26, back to themidpoint of battery 10. It will be noted that this circuit cannot becompleted unless the signals SS and SN of the conflicting track are intheir stop position. Completion of this circuit effects energization ofthe control relay 2Z and the indicating relay 2R.

. lV-ith the control relay 2Z energized to the right, it being assumedthat current flowing from the positive terminal of the battery 10 willoperate relay 2Z towardthe' right, the

following circuits for energizing the derail machines DRE and DR f areclosed, this on the assumption that the approach locking relay AL isenergized and that the approaching train has not yet approached withinthe approach locking zone preferably extending braking distance in therear cf the signal SE :-beginning at the terminal B of a suitablebattery, front contact 28 of the approach locking relay AL, wire 29,contact" 30, wire 31, polar contact 32, of the control relay 2E assumingits right-hand position, wire 33,

and then the two circuits divide through wires 84 and 35 to the twoderail machines DRE and D 3V, and thence to the common return Wire Cconnected to the other terminal of said battery. The completion of thesecircuits causes operation of the derail machines and DEVI, and as soonthese machines have been unlocked the following circuit for the relay 2Wis broken: beginning at the terminal B, wire 36, contactB? of the derailmachine DRE, Wires 38, 39 and 40, contact 41 of the derail machine DEVI,wires 4-2 and 43, inding ofthe-relay 276, 1 to the terminal C connectedto the other side of said battery.

he breaking of this circuit for the relay TWP causes the contact 4'5 ofthis relay 2W to assume its retracted position, thereby reversing thepolarity of the current applied to the relay 20S, and causing therelay-20S to assume its (lo-energized position and mo men-t thereafteragain assume its energized position. This is accoinipli lied by openingof a circuit starting at the negative terminal of battery thro-ugh46,4?, &8, 49, 14, i5, 8, 20$, 9 and 56; and closing of a circuit startingat the positive terminal of battery 5-0 understood that relay 2Z cannotbe operated unless relay 20S is energized, butif relay 2Z has once beenenergized it may be held up through back contact 16 of relay 20S, therelay being suiiiciently slow dropping as conventionally shown toprevent it dropping during dropping of the contact 16.

De-energization of the relay 20S Opens the line circuit including theline wire 15 and effects de-energization of the relay 2R in theiiterlocliing tower IT, but such die-energization of relay 20S does noteffect de-energiation of the contr l relay 22?, because this controlrelay 2:1 is maintained stuck up through the following stick circuit:beginning at the positive terminal of the battery 50, wire 51, contact52, wire 53, neutral contact 54 of the relay 2. 1, wire 55, contact 16of the relay 20S in its retracted position, Wire 1'2, winding of therelay 22'. wires 18 and 19, contact 20 of the signal. SS, wire 21,signal blade contact 22 of the signal SN,-wires 23 and 56., back to themidpoint of the battery 50. Momentary dc-cnergization of the relay2Rcauses the folio ring circuit to be momentarily completed for theindicating lamp 1: beginnin atthe positive terminal of the battery 10,wires 11 and 12, contact of lever L wires 57 back contact 58 of therelay v e indicatin, lamp 1, wires 62,63, 64, and baclr to the midpointof the battery 10. This momentary illumination of the indicating lamp Iinforms the operator that the derails have been started on their cycleof operation from their active to their inactive position or ice versa,and when these deraiis have completed this cycle of operation the sameenergizing circuit except that contacts 37 and 84 assume their dottedposition for the relay 216 1 i's'again completed, the contact 45 of thisrelay is operated to its attracted position, thereby again reversing theaolarity of current applied to the relay 20 and again offectingmomentaryillumination of the inclicating lamp 1, for reasons just explained,

When the operator has received this second flash of the indicating lampI he will return his lover L to the neutral position and will operatethe lever L to the right-hand po sition in order to clear the east boundsignal SE. This movement of the lever L effects closure of'the followingcircuit :,beginning at the positive terminal of the battery 10, *ires 11and 66, contact of thelover L wire 67, winding of the relay 1R, linewire 68, front contact 69 of the track relay T, wire 70, winding of therelay iZ, wires 71 and 19, contact 20 of the signal SS, wire 21, contact22 of the signal SN, wires 23, 24, C, 25 and 26,

aclr to the midpoint of battery 10. It will be noted that the circuitjust traced cannot be closed unless the track circuit containingthe'traclr relay T is unoccupied. The completion of the circuit justtraced energizes the control relay lZ towa "d the right,the re lay lZbemg connected to so operateyand with this relay lZ energized toward theright the east bound signalSE is permitted to clear, providing trafficconditions in advance of the signal SE, are proper as manifested by thehome relay EH and providing that both the derail DRE and the derail DE/V have been moved to their abnormal closed track posit-ion. Thiscircuit for the signal SE may be traced as follows:beginning atthetermi-' nal B of aisuitable battery, neutral contact 72 of the relay1Z,wire 73, polar contact 74;

of therelay lZ toward the right, Wire 75,

neutral contact 76 of the home relay EH,

wire 77,.polar contact'78 of the home relay" EH toward the ri 'ht(assuming clear traffic conditions ahead) clear wire v7 9, mechanism ofthe signal SE, (for itsvcolored signal lamp if a light signal is used)wires 80 and8l, contact v82 of the derail DRE, wire 88, contact84:of'the derail DEW, wire 85 to the other terminal C of said battery. Itis thus noted that the signal SEcannot clear unless the operator hasoperated the control relay lZ toward the right, traffic conditions asmanifested by. the home. relay EH are clear, and unless thederaiL-machines DRE and DRlV are in their closed track position. 7 Thecompletion of the circuit forenergizing the control relay lZ alsoeffectsenergization of the indicating relay 1R. Also, with thelever L inits right hand position the relay 1X is energized to'the right, forobvious reasons. VViththe relay 1R energized and the relay 1X energizedtoward theright, the following circuit for the miniature signal so isclosed: beginning at thepositive terminal of the battery 10, wires 11and 66, contact ofthe lever L wires 87 and .88, front contact 89 of therelay 1R, wire 90, contact Slof the relay 1X toward the right, wire 92,lamp of the miniamidpoint ofbattery 10. r

If now the train in question accepts the ture signal .86, wires 93 and65, back to the signal SE and proceeds into the tracksectionv betweenthe signal SE and SW, the track relay ,T is de-energized, therebyopening its contact 69 and effecting de-energization of the controlrelay lZ and the indicating relay 13. With the relay 1R assuming itsretracted position and the lever L in its right-hand position thefollowing circuit for the track occupancy indicating lamp 256 is closed:beginning at the positive terminal of the bat-, tery 10, Wires 11 and66, contact of the lever L wires 8'? and 88, contact 89 of the relay 1Bin its retracted position, wire 95, signal lamp te, wires 96, 64 and 65,back to the midpoint of battery 10. Also, de-energization of theindicating relay 1R will effect extinguishment of the signal lamp 86, sothat the op erator is informed that the train is passing through the'track section between thesignals SE andSlV.

By reason of the fact that the approach locking relay AL is controlledby an ap proachlockmg'circuit such as disclosed in my prior application,to which reference has been made, the derails DRE and DRl V cannot beoperated if there is a train approaching from either. direction,unless-this train has accepted the distant signal (not shown) at cautionor stop, all as, explained in "said prior application. From this it willappear that the derail machines DRE and DEW cannot be operated in thefaceof an approaching train. Further, it will be noted that thesignalsfSE and SW cannot be cleared unless both derails are in theirabnormal continuoustrack position. 3

Applicant has thus provided a system requiring onlytwo line wires andacommonreturn Wire for safely. operating the derails and signals at arailroad crossing, the cir-;

cuit arrangement being such that the operator is informed as to theoperation of the derails, the position of signals and the occupancy ofthe track section in which such derailsarelocated thiss stem havin all.

of its interlocking features located; at the distant interlocking plant,so that any line troublebetween the distant interlocking plant and theinterlocking tower cannot possibly cause false operationof the derailsortheclearing of signals, unless it is safe to so" operate them. Inpractice the track NSof the other system will be protected by suitableinterlocked signals which are preferably controlled in the same way.

Having thus shown and described one rath-' er specific embodiment of thepresent invention it is desired to be understood that the particularcircuit arrangement illustrated has been selected to facilitatedescription of the invention, and its operatingcharacteristics andunderlying'principles ofoperatlon, and has not been selected with thelntent of showing the scope of the. invention or the exact constructionpreferably employed in practicing the same, and that various changes,mod1ficat1ons,'and additions may be made to adapt the invention to thepart cular railway system to which it is to be applied, all without tosaid tower, a track circuit for manifesting the passage of a train oversaid derails 1ncludlng a track relay, a front contact of said trackrelay included in the circuit for said control relay, indicating meansat said tower included in the circuit of said control relay, and a leverfor controlling the flow of current in said control relay, whereby saidderails can be operated and the occupancy of said track circuit can beindicated over the same line circuit. i

2. In a remotely controlled interlocking system, the combination withtwo railroads crossing each other, of derails on one of said roads toprevent a train on said road crossing the other road, a controlrelay forcontrolling said derails effective only if signals governing trafficover the other road are at'stop, a distant interlocking tower, a circuitincluding said control relay leading to said tower, a track circuit formanifesting the passage of a train over said derails including 'a trackrelay, a front contact of said track relay included in the circuit forsaid control relay, indicating means at said tower included in thecircuit of said control relay, a lever for controllingthe flow ofcurrent in said control relay, whereby said derails can be operatedandthe occupancy of said track circuit can be indicated over the same linecircuit, signals associated with saidderails, and other means forcontrolling said signals from said distant tower. V

3. In a remotely controlled interlocking system, the combination withtwo railroad systems crossing each other, of wayside signals on onesystem for blocking the movement of trains over said crossing, derailsassociated with said signals for enforcing obedi ence of'trains to saidsignals, a derail-relay controlled from a distant tower for controllingsaid derails, approach locking means for preventing operation of saidderails by said derail relay unless there is no train approaching in anapproach zone which did not pass an adverse signal, a signal controlrelaycontrolled from said distant towerfor controlling said signals, andmeans for preventing control of said signals by said signal relay unlesstraflic conditions in advance of'sucli signals are favorable 4. In aremotely controlled interlocking system, the combination with tworailroad systems crossing each other, of wayside sig- I; nals on onesystem for blocking the movement of trains over said crossing, derailsassoclated with said signals for enforcing obedience of trains to saidsignals, a derail relay controlled from a distant tower for controllingsaid derails by said derail relay unless there is no train approachingin an approach zone which 'did not pass an adverse signal, a signalcontrol relay controlled from said distant tower for controlling saidsignals,

means for preventing control of said signals by said signal relay unlesstrafiic conditions 1n advance of suchfs gna'ls are favorable,

trolling said derails, approach locking means for preventin operation ofsaid derails by said derail relay unless there is'no train approachingin an approach zone which did not pass an'adverse signal, a signalcontrol relay controlled from said distant tower for controllings'aid-signals, means for preventing control of said signals bysaidsignal relay unless trafiic conditions in advance of such signalsare favorable and means for indicating at said'tower the passage of atrain over said derails.

6. In a remotely controlled interlocking system, the combination withtwo railroad systems crossing. each other, of wayside signals on onesystem for blocking the movement of trains over said crossing, derailsassociated with said signals for enforcing obedience of trains to saidsignals, a derail relay controlled from'a distant tower for controllingsaid derails-by said derail relay unless there is no train approachingin an approach zone which did not pass an adverse signal, a signalcontrol relay controlled from said distant tower for controlling saidsignals, means for preventing control of said signals by said signalrelay unless traflic conditions in ad Vance of such signals arefavorable, other signals on said other railroad system for governing themovement of trains over said crossing, means for preventing operation ofsaid derailsunless said other signals are at stop, and means forindicating at said tower the passage of a train over said derails.

7. In a remotely controlled interlocking system, the combination withtwo railroads crossing each other, of derails on one of said roads forpreventing a train on said road crossing the other road, signals forgoverning the movement of trains over said derails, power operated meansfor operating said derails, a control relay for controlling said poweroperated meansand controlled from a central oflice, meansfor indicatingat said office the response of said power operated means to said controlrelay, other signals on the other of said roads for governing thecrossing of trains over said one road, means for preventing operation ofsaid power operated means if one of said other signals indiv catesproceed, and means for clearing said first mentionedsignals effectiveonly it said derails assume their closed track position.

8. In a remotely controlled interlocking system, the combinationwith tworailroads crossing each other, of derails on one of said roads forpreventing a train on said road crossingthe other road, signals forgoverning the movement of trains over said derails, power operated meansfor operating said de rails, a control relay for controlling said poweroperated means and controlled from a central otfice, meansfor-indicating at said oliice the response of said power operated meansto said control relay, other signals on the other of said roads forgoverning the crossing of trains over said one road, means forpreventing operation of said power operated means if one of said othersignals'in- 'dicates proceed, and means for clearing said firstmentioned signals en' ective only it said derails assumetheir closedtrack position and there is no train approaching at speed on said oneroad.

9. In a remotely controlled interlockingsystem, the comblnation with twoItllI'OEtClS crosslng each other, of derails on one of said roads forpreventing a train on said road crossing the other road, signals forgoverning the movement of trains over said derails, power operated meansfor operating said derails, a control relay for controlling said poweroperated means and controlled from a central oflic'e, means forindicating at said office the response of said power operated means tosaid control relay, other signals on the other of said roads forgoverning the crossing of trains over said one road, means forpreventing operation of said power operated means if one of said othersignals indi' V cates proceed, means forclearing said first mentionedsignals effective only it said derails assume their closed trackposition, and means for indicating at said central oflice the passage ofa train over said derails.

10. Ina remotely controlled interlocking system, the combination withtwo railroads crossing each other, of derails on one of said roads forpreventing a train on said road crossing the other road, signals forgoverning the movement of trains over said derails, power operated meansfor operating said derails, a control relay for controlling said poweroperated means and controlled from a central oliice, means forindicating at said office the response of said power operated means tosaid control relay, other signals on the other of said roads forgoverning the crossing of trains over said one road, means forpreventing operation of said power operated means if one of said othersignals indicates proceed, means for clearing said first mentionedsignals efiective only if said derails assume their closed trackposition and there is no train approaching at speed on said one road andmeans for indicating at said central office the passage of a train oversaid derails.

11. a remotely controlled interlocking system the combination with tworailroad systems crossing each other, of wayside signals on one systemfor blocking the movement of trains over said crossing, derailsassociated with said signals for enforcing obedienceof trains to saidsignals, a derail relay controlled from a distant tower for controllingsaid derails, approach locking means snnew on N. wrenr.

